156 CLASS DECANDRIA. 



medicinal rhubarb ; this is obtained from the roots, which arc 

 thick, fleshy, and yellow. In this root are TafMdes of oxalate 

 of lime, which yield a large proportion of rhubarb. At Fig. 

 140, J, is a flower of the genus Rheum. 



a. In becoming interested in the study of plants, we naturally wish to know 

 soraetliing about tliose whicli we are in the habit of using for food or medicine, or 

 to which, as in the laurcd of the ancients, allusions are often made in the books 

 we read. But no one can become a practical botanist without much observation of 

 native plants. They must be sought in their own liomes, in the clefts of rocks, by 

 the side of brooks, and in the shady Avoods ; it is there we find nature in her un- 

 vitiated simplicity. We do not go to the crowded city to find men exhibitmg, un- 

 disguisedly, the feelings of the heart ; and the llower transplanted from its rural 

 abodes, often exhibits in the green-house a metamorphosis which conceals its real 

 character. 



LECTUKE XXIX. 



DECA^DKIA, TEN STAMENS. 



215. The number of stamens in plants of this class must not 

 only be ten, l^ut these must be distinct from each other ; that 

 is, neither united by their filaments nor by their anthers. 

 Other classes may also have ten stamens ; but circumstances 

 respecting the situation of these organs distinguish these classes 

 from each other. 



216. Order Monogynia^ one ])istil. — We here find some plants 

 \^A\\\ ])apilionaceoiis corollas J these, because XhQiv fila7nents are 

 not united^ are separated from the natural family to which they 

 belong, and which are mostly in the artificial class Diadelphia. 

 The wild indigo {Bajytisia) has ten stamens, distinct ; yellow, 

 papilionaceous flowers, and leguminous fruit. This plant be- 

 comes black in drying. The Cassia fistula^ a native of the 

 Indies, contains in its legume a pulp secreted from the endo- 

 carp which is much valued in medicine, and known by the 

 name of cassia. The Cassia senna furnishes the sennet used in 

 medicine ; this species grows in Egypt and Arabia. Cassia 

 niaryleondica is called American seiina on account of its medici- 

 nal qualities. Cassia nictitans has small yellow flowers and 

 beautiful pinnate leaves ; it is called the American sensitive- 

 plant, as it closes its leaves when touched, and folds them at 

 night. A plant, called, by the Indians, red-bud (Cekcis canor 

 densis)^ belongs to this class, and to the great natm'al fam 

 ily, LegmninoscB. It is a large tree, appearing early in spring, 

 laden with clusters of fine crimson flowers, resembling at a 



a. Remarks.— 215. Is there any class except the tenth in which the flowers have ten s'aniens ?— 

 21 G Order MoHOf^ynia— »Wild Indigo — ^^Cassia — Cercis. 



